In recent years, an image forming apparatus such as an MFP (Multi Function Peripheral) is used to form an image on a sheet. A decolorable coloring agent such as ink containing leuco dye is used to print an image on a sheet in order to make it possible to erase the image formed on the sheet and reuse the sheet. High temperature is applied the decolorable coloring agent to erase the decolorable coloring agent.
Therefore, when the sheet is reused, the sheet is heated using an erasing apparatus to erase the image formed on the sheet. The erasing the image formed on the sheet as explained above is referred to as “decoloring” in the following explanation.
In the decoloring apparatus, a platen roller and a heat source are arranged to be opposed to each other across a conveying path for the sheet. The decoloring apparatus conveys the sheet to between the platen roller and the heat source to thereby heat the sheet and erase the decolorable coloring agent.
If both the surfaces of the sheet are decolored, since the front surface and the rear surface of the sheet are decolored, excess operation power is consumed in the heating of the sheet. The sheet may be unable to be sufficiently preliminarily heated before the sheet reaches the position of the platen roller. Therefore, the decoloring is insufficient or heat higher than necessary needs to be applied to the sheet.
Further, since the sheet once used is conveyed to the decoloring apparatus, highly likely that the leading end portion of the sheet is bent or folded. Therefore, be difficult to guide the leading end of the sheet to a nip section in a stable state.